Pump

ABSTRACT

A pump includes a body, and first and second rotors. A chamber is defined in the body. First and second inlets and first and second outlets are defined in the body in communication with the chamber. The first rotor is rotatably received in the chamber and connected with a first shaft. The first rotor is generally circular with a blade extending outward therefrom. The blade includes first and second mating surfaces. A third mating surface is formed at the blade between the first and second mating surfaces. The second rotor is rotatably received in the chamber and connected with a second shaft. The second rotor is generally circular with an engaged recess inward defined therein for mating with the blade of the first rotor. The engaged recess includes first and second engaged surfaces for mating with the first and second mating surfaces. A third engaged surface is formed at the bottom of the engaged recess between the first and second engaged surfaces for mating with the third mating surface of the blade.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pump, and particularly to a pumphaving a high compression ratio and can fully exhaust fluid drawn intothe chamber and preventing overheating during a compression cycle.

2. Prior Art

In general, a pump includes a body in which a chamber, an inlet and anoutlet both in communication with the chamber are defined, and rotorsrotatably and fitly received in the chamber as close running fit. Fluidis drawn into the chamber through the inlet and expelled out through theoutlet by the rotors. Pumps are applied in different fields as differentapparatuses such as a vacuum air pump, an air compressor pump, and acompressor pump. Conventional pumps were disclosed in Taiwan patentapplication Nos. 88112386, 88115060, 89210884, 89213279, 91213279,91206505 and 91111929 and U.S. Pat. Nos. 2,164,462, 3,188,822, 3,426,525and 4,138,848.

However, each conventional pump has a dead compression zone due to theconfiguration of the rotors. The dead compression zone makes some of thecompressed fluid remain in the chamber during a compression cycle, whichreduces the transporting volume of the compressed fluid and thecompression ratio of the pump. Thus, the fluid drawn into the chambercannot be fully exhausted by the conventional pump.

In the former case, fluid might be not secured to inpour and flux thechamber during a compression cycle in view of the leavings fluid shouldaffects the fluid into the chamber, resulting in reflux which adverselyaffects fluid flowing into the chamber. In other words, only an inletand an outlet of the chamber cannot resist refluent therefrom. Thus, itis complicated to control the compression ratio of the pump, such as thecompression ratio and the transporting volume of the pump is furtheraffected.

In addition, the rotors are fitly received in the chamber as closerunning fit. It is complicated to fabricate the rotors and the chamberdue to the close running fit. Furthermore, the phenomena of thermalexpansion appear on the rotors during the compression cycle, whichadversely affects the close running fit and causes friction between therotors and the chamber. Additionally, the chamber have scale at innerwall of the chamber after a period of use and so reduce the sizethereof, which also adversely affects the close running fit and causesfriction between the rotors and the chamber. Thus, the pump may beoverheated due to the friction and so can not work normally.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a pumpwith a high compression ratio and without a dead compression zone andcan fully exhaust fluid drawn into a chamber of the pump.

Another object of the present invention is to provide a pump which isready to control the compression ratio thereof.

Further object of the present invention is to provide a pump have goodperformance between the rotors and the chamber, in which the rotors isable to clean inner wall of the chamber during a compression cycle, anda buffer area which is a channel defined in a body in communication withthe chamber, which is ready to fabricate and prevents overheating duringa compression cycle thereby facilitating to work stably.

To achieve the above-mentioned objects, a pump in accordance with thepresent invention includes a body, and first and second rotors. Achamber is defined in the body. First and second inlets and first andsecond outlets are defined in the body in communication with thechamber, and each of which has a check valve therein for preventingreflux therefrom. The first rotor is rotatably received in the chamberand connected with a first shaft. The first rotor is generally circularwith a blade extending outward therefrom. The blade includes first andsecond mating surfaces. A third mating surface is formed at the bladebetween the first and second mating surfaces. The second rotor isrotatably received in the chamber and connected with a second shaft. Thesecond rotor is generally circular with an engaged recess inward definedtherein for mating with the blade of the first rotor. The engaged recessincludes first and second engaged surfaces for mating with the first andsecond mating surfaces. A third engaged surface is formed at the bottomof the engaging recess between the first and second engaged surfaces formating with the third mating surface of the blade.

Other objects, advantages and novel features of the present inventionwill be drawn from the following detailed embodiment of the presentinvention with attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevational view of a pump in accordance withan embodiment of the present invention;

FIG. 2 is an enlarged schematic side elevational view showing a firstrotor mating with a second rotor;

FIGS. 3A-3I are schematic side elevational views of successive positionsof the first and second rotors for explaining and understanding theoperation of the pump;

FIG. 4 is a schematic side elevational view showing the first rotor withtwo blades and the second rotor with corresponding two engaged recesses;

FIG. 5 is a schematic side elevational view showing the first rotor withthree blades and the second rotor with corresponding three engagedrecesses;

FIGS. 6 is a schematic side elevational view showing a first rotor and asecond rotor in accordance with another embodiment of the presentinvention;

FIGS. 7 and 8 are schematic. side elevational views of successivepositions of the first and second motors for explaining andunderstanding the second rotor wiping inner wall of the chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a pump 1 of the present invention includes a body 2and first and second rotors 3, 4. A chamber 20 is defined in the body 2and includes first and second circular portions in communication witheach other. The first and second portions of the chamber 20 respectivelyreceive the first and second rotors 3, 4 therein. First and secondinlets 21, 22 and first and second outlets 23, 24 are defined in thebody 2 in communication with the chamber 20. The first inlet 21 isopposite to the second outlet 24 which is defined between the firstoutlet 23 and the second inlet 22. Each of the first and second inlets21, 22 and the first and second outlets 23, 24 has a check valve (notshown) therein for preventing reflux therefrom. A channel 25 is definedin the body 2 in communication with the second portion of the chamber 20and surrounds an end of the chamber 20 for providing a buffer areathereby absorbing offset of the second rotor 4 during a compressioncycle. Thus, friction between the second rotor 4 and the body 2 isreduced thereby preventing overheating.

The first rotor 3 connects with a first shaft 30 which connects with amotor (not shown) for being driven to rotate. The first rotor 3 isgenerally circular with a blade 31 extending outward therefrom. Alsoreferring to FIG. 2, the blade 31 includes symmetrical first and secondmating surfaces 311, 312. The profile curve of the first mating surface311 is a reflection curve of that of the second mating surface 312. Athird mating surface 313 is formed at the blade between the first andsecond mating surfaces 311, 312.

The second rotor 4 connects with a second shaft 40 which connects withthe motor for being driven to rotate. The second rotor 4 is generallycircular with an engaged recess 41 inward defined therein for matingwith the blade 31 of the first rotor 3. Also referring to FIG. 2, theengaged recess 41 includes symmetrical first and second engaged surfaces411, 412 for mating with the first and second mating surfaces 311, 312.The profile curves of the first and second engaged surfaces 411, 412 areconjugate curves of those of the first and second mating surfaces 311,312, respectively. A third engaged surface 413 is formed at the bottomof the engaged recess 41 between the first and second engaged surfaces411, 412 for mating with the third mating surface 313 of the blade 31.

Referring to FIGS. 3A-3I, successive positions of the first and secondrotors 3, 4 are shown for explaining and understanding the operation ofthe pump 1. FIGS. 3A-3D show that fluid is drawn into the chamber 20through the check valves of the first and second inlets 21, 22. FIGS.3E-3G show that the first and second mating surfaces 311, 312 of thefirst rotor 3 rotatingly mate with the first and second engaged surfaces411, 412 of the second rotor 4 thereby compressing and exhausting thefluid through the check valves of the first and second outlets 23, 24.Further rotation of the first and second rotors 3, 4 makes the thirdmating surface 313 mate with the third engaging surface 413 therebycontinuously expelling the fluid out of the chamber 20 through the firstand second outlets 23, 24. Referring to FIGS. 3H-3I, at the end of thecompression cycle, it is a start to draw the fluid into the chamber 20through the first inlet 21. Since the channel 25 absorbs offset of thesecond rotor 4 during the compression cycle, friction between the secondrotors 4 and body 2 is reduced thereby preventing overheating during thecompression cycle.

As mentioned above, due to the configuration of the first and secondrotors 3, 4, and the check valves of the inlets 21, 22 and the outlets23, 24, the pump 1 of the present invention can fully exhaust the fluidthrough the outlets 23, 24 and ready to control the compression ratiothereof. Thus, the pump 1 has a high compression ratio and a hightransporting volume. Due to the channel 25, the second rotor 4 is notclose running fit with the chamber 20 and so the pump 1 of the presentinvention is ready to fabricate. Since the channel 25 absorbs offset ofthe second rotor 4 during the compression cycle thereby reducingfriction between the second rotor 4 and the body 2, the pump 1 preventsoverheating during the compression cycle thereby facilitating to workstably.

Referring to FIGS. 4-5, the first and second rotors 3′, 4′ may have morethan one blade 31′ and reces engaged s 41′ respectively. In FIG. 4, twoblades 31′ are symmetrically formed at the first rotor 3′ and twoengaged recesses 41′ are symmetrically defined in the second rotor 4′for respectively mating with the two blades 31′. In FIG. 5, three blades31′ are equally spacedly formed at the first rotor 3′ and three engagingrecesses 41′ are equally spacedly defined in the second rotor 4′ forrespectively mating with the three blades 31′.

A pump of another embodiment of the present invention is shown in FIGS.6-8. Compared with the above-mentioned embodiment, the channel 25 of theabove-mentioned embodiment is not defined in body of the anotherembodiment. The blade of the first rotor 3″ and the engaged recess ofthe second rotor 4″ of the pump in accordance with the anotherembodiment are differently configured compared with the above-mentionedembodiment. The profile curve of the first mating surface 311″ of thefirst rotor 3″ is a reflection curve of that of the second matingsurface 312″ but has a different curve length from that of the secondmating surface 312″. The profile curves of the first and second engagedsurfaces 411″, 412″ are conjugate curves of those of the first andsecond mating surfaces 311″, 312″, respectively. During the compressioncycle, an apex 414″ formed at the junction of the first engaging surface411″ and a peripheral surface of the second rotor 4″ wipes an inner wall201″ of the chamber 20″ to clean the inner wall 201″ thereby preventingthe inner wall 201″ from begriming. Thus, friction between the rotor 4″and the body 2″ is reduced thereby preventing overheating during thecompression cycle.

It is understood that the invention may be embodied in other formswithout departing from the spirit thereof. Thus, the present examplesand embodiments are to be considered in all respects as illustrative andnot restrictive, and the invention is not to be limited to the detailsgiven herein.

1. A pump comprising: a body, a chamber being defined in the body, afirst inlet and a first outlet being defined in the body and incommunication with the chamber; a first rotor rotatably received in thechamber and connected with a first shaft, the first rotor beinggenerally circular with a blade extending outward therefrom, the bladecomprising first and second mating surfaces, a third mating surfacebeing formed at the blade between the first and second mating surfaces;a second rotor rotatably received in the chamber and connected with asecond shaft, the second rotor being generally circular with an engagedrecess inward defined therein for mating with the blade of the firstrotor, the engaged recess comprising first and second engaged surfacesfor mating with the first and second mating surfaces, a third engagedsurface being formed at the bottom of the engaged recess between thefirst and second engaged surfaces for mating with the third matingsurface of the blade.
 2. The pump as claimed in claim 1, wherein asecond inlet and a second outlet are further defined in the body incommunication with the chamber.
 3. The pump as claimed in claim 2,wherein the first inlet is opposite to the second outlet and locatednear the position where the third mating surface and the third engagedsurface begin meshing, the first outlet located near the position wherethe blade and the recess of the first and second rotors respectivelybegin meshing.
 4. The pump as claimed in claim 3, wherein the secondoutlet is defined between the first outlet and the second inlet.
 5. Thepump as claimed in claim 4, wherein each of the first and second inletsand the first and second outlets has a check valve therein forpreventing reflux therefrom.
 6. The pump as claimed in claim 5, whereina plurality of blades is equally spacedly formed at the first rotor, anda plurality of engaged recesses is equally spacedly defined in thesecond rotor for respectively mating with the blades.
 7. The pump asclaimed in claim 6, wherein the profile curve of the first matingsurface is a symmetrical reflection curve of that of the second matingsurface, and the profile curves of the first and second engaged surfacesare conjugate curves of those of the first and second mating surfaces,respectively.
 8. The pump as claimed in claim 7, wherein a channel isdefined in the body in communication with the chamber and surrounds anend of the chamber for providing a buffer area thereby absorbing offsetof the second rotor during a compression cycle.
 9. The pump as claimedin claim 6, wherein the profile curve of the first mating surface of thefirst rotor has a different curve length from that of the second matingsurface, the profile curve of the first mating surface is a reflectioncurve of that of the second mating surface, and the profile curves ofthe first and second engaged surfaces are conjugate curves of those ofthe first and second mating surfaces, respectively.
 10. The pump asclaimed in claim 9, wherein during a compression cycle, an apex formedat the junction of the first engaged surface and a peripheral surface ofthe second rotor wipes an inner wall of the chamber to clean the innerwall thereby preventing the inner wall from begriming.
 11. A pumpcomprising: a body, a chamber being defined in the body and comprisingfirst and second circular portions in communication with each other,first and second inlets and first and second outlets being defined inthe body in communication with the chamber; a first rotor rotatablyreceived in the first portion of the chamber and connected with a firstshaft; a second rotor rotatably received in the second portion of thechamber for mating with the first rotor, the second rotor connectingwith a second shaft.
 12. The pump as claimed in claim 11, wherein eachof the first and second inlets and the first and second outlets has acheck valve therein for preventing reflux therefrom.
 13. The pump asclaimed in claim 12, wherein the second outlet is defined between thefirst outlet and the second inlet.
 14. A pump comprising: a body, achamber being defined in the body, a first inlet and a first outletbeing defined in the body and in communication with the chamber, achannel being defined in the body in communication with the chamber; afirst rotor rotatably received in the chamber and connected with a firstshaft; a second rotor rotatably received in the chamber for mating withthe first rotor, the second rotor connecting with a second shaft. 15.The pump as claimed in claim 14, wherein the channel surrounds an end ofthe chamber for providing a buffer area thereby absorbing offset of thesecond rotor during a compression cycle.